1. Field of the Invention
The present invention relates to a device, a computer program product, and a method for speech synthesis.
2. Description of the Related Art
Speech synthesizing devices have been applied to voice services for traffic information and weather reports, bank transfer inquiry services, and interfaces of humanlike machines such as robots. The speech synthesizing devices therefore need to offer synthetic speeches that sound clear and natural.
An example of such a technology conducts speech synthesis for a sentence containing fixed segments that are fixed information and non-fixed segments that are variable information (see JP-A H8-63187 (KOKAI), for example). Concerning the fixed segments, time-changing patterns of fundamental frequencies (hereinafter, referred to as “F0 patterns”) are extracted and stored from speeches of the sentences produced by a human. Concerning the non-fixed segments, F0 patterns corresponding to all combinations of the number of syllables of words or phrases and stresses of the words or phrases, which are expected to be input, are stored. A synthetic speech that sounds natural as a sentence is generated by selecting or generating F0 patterns for each of fixed segments and non-fixed segments and then connecting the F0 patterns.
With conventional speech synthesizing devices, however, because a synthetic speech of only a single sentence is generated, unnaturalness accompanied by connecting synthetic sounds tends to be noticeable.